last updated Thursday, May 18, 2006

Meeting 15 (Acetyl Ferrocene)

Important Announcements:

1. The proposal is due on May 26, 2006 at 5 pm in YH 3077E (If you have problems please see me asap!). The proposal has to be submitted to turnitin.com as well (same course ID as before).

2. The next quiz will be administered on May 25, 2006 at 12 pm. It will cover the esterification and electrophilic aromatic substitution.

3. In the lab, you will only carry out the acylation of ferrocene, but not the synthesis of ferrocene. This part will be done individually.

Homework assignments (due May 23/24, 2006)

1. Referring to the synthesis of ferrocene, answer the following questions.

a. Cyclopentadiene is not commercial available. How is it obtained in the lab? What type of reaction is this and what is the driving force for the reaction?

b. Cyclopentadiene is significantly more acidic than cyclopentane and cyclopentene? Explain.

c. Dimethylsulfoxide used as a solvent in this reaction. Rationalize this choice.

2. Referring to the synthesis of acetyl ferrocene, answer the following questions.

a. How is the acylium ion generated in the lab? Which advantage does this method have?

b.Why is the acylium ion considered a weak electrophile? Which implication does this observation have?

c. The pH-value is adjusted to pH=5-6. Explain briefly why and how. Show pertinent chemical equations.

d. Sketch a TLC plate for the crude product using SiO₂ as stationary phase and hexane:dichloromethane=5:1.

e. Why is it important to start with a low polarity solvent when performing column chromatography?